Unsaturated ether or ester derivatives of polyhydric phenols are well known as a class of compounds that can be cured or crosslinked to produce insoluble products which exhibit good solvent resistance and mechanical properties as well as high heat distortion temperatures. Such unsaturated ethers are crosslinked by reaction with catalytic or stoichiometric curing agents, i.e., polyfunctional curing agents, to produce tough, heat resistant products which are processed by conventional methods into sheets, laminates with fiber glass or other reinforcements, or shaped articles and the crosslinked products are also useful in adhesive formulations. Certain of the unsaturated ethers cure into such products merely upon the application of heat without the necessity of a curing agent. Such materials are termed self-curing.
As indicated, much of the technology is broadly conventional. The disclosure of Zahir et al, U.S. Pat. No. 4,100,140, is illustrative. The compound 2,2-bis(4-hydroxyphenl)propane, also known as bisphenol A or BPA, is converted to the sodium salt and reacted with allyl chloride to produce the allyl ether of BPA, i.e., 2,2-bis(4-allyloxyphenyl)propane. The diallyl ether is converted to the diallyl-substituted BPA which is cured, but the diallyl ether is also curable without rearrangement. Curing takes place, for example, by reacting the diallyl ether with an imide-containing curing agent.
Other types of unsaturated derivatives of polyhydric phenols which are cured by such conventional techniques include unsaturated ester derivatives such as the acrylate and methacrylate esters of polyhydric phenols described by Zahir et al, U.S. Pat. No. 4,468,524.
On some occasions, the cured products which provide the more desirable properties, particularly in high temperature applications, are produced from unsaturated derivatives of aromatic phenolic compounds wherein some or all of the rings share common atoms with other rings of a polycyclic structure. It would be of advantage to provide a novel class of unsaturated derivatives of phenolic compounds having a plurality of rings within the molecular structure. Such unsaturated derivatives cure, with or without added curing agents, upon application of heat.